Nothing has been revealed by police about what happened to Mr Harrington, 23, after he disappeared from the Logan suburb of Woodridge.

Mr Harrington, who is not a suspect in this case, was last seen on January 25.

Cory Breton, 28, last made contact with his family on January 23 and mother-of-three Iuliana Triscaru, 31, was last seen a day later.

The trio were initially believed to be travelling together, however by last week, police held grave concerns for their safety.

Mr Harrington had made no contact with friends or family after his disappearance. None of the three had touched their bank accounts or mobile phones, however it was later revealed Mr Breton had withdrawn $3000 from his account before he went missing.

As police stepped up the search for the missing group, it was revealed Mr Breton and Ms Triscaru were drug users and were known to police for “low-level” incidents.

Iuliana Triscaru and Cory Breton.Source:Supplied

Two of Mr Breton’s cars were found, including one at a ferry carpark, which lead to suspicions the trio were headed for Stradbroke Island.

But inquiries on the island produced no solid leads.

“We’re taking it very seriously,” Detective Superintendent Dave Hutchinson said last week.

“We’re hoping for the best but planning for the worst.

“It is still possible they’ve gone away together ... it just can’t be explained.”

As days of unanswered questions ticked into a fortnight, the families of the missing trio made desperate public appeals for information.

Ms Triscaru’s mother, Victoria, fought back tears as she fronted the media on Tuesday.

“I miss her. She’s a very good girl and a very good mum,” she said.

“The kids ask me all the time, ‘where mummy, where mummy?’.

“I’d be happy with just one call saying ‘mama, I’m still alive’. That’s it.”

Mr Breton’s partner Miranda said she was thinking of “a million and one different scenarios” that would explain his absence.

Former Woodridge High School student Lelan Harrington.Source:No Source

“Unfortunately, my gut feeling is not very good,” she said.

“Nothing adds up ... it’s like a big puzzle that’s missing a lot of pieces.”

As baffled detectives considered foul play, on Wednesday, Lelan Harrington was found — alive and well — at a house in Logan.

A crime scene was set up at his Kingston home and he was taken into police custody for hours of intense questioning, however police said he was not considered a suspect.

Police have not revealed anything of what Mr Harrington may told them about what happened to him, or the possible fate of the other two.

But after weeks of futile searching for Ms Triscaru and Mr Breton, suddenly, events began to escalate.

The case shifted from a missing persons case to a homicide investigation. On Wednesday afternoon, hours after Mr Harrington was found, police had descended on a vacant site at the end of Mudgee Rd in Kingston and launched water, land and air searches.

By the early evening, they had started to arrest what would be a final total of six people — five men and one woman — in relation to the missing pair.

In one dramatic arrest, armed officers swooped on the BMW of two accused killers on a Brisbane motorway.

Around the same time, police searching a dam at the end of Mudgee Rd in Kingtson found a large, metal toolbox.

Holes drilled in the sides allegedly helped their makeshift coffin sink to the bottom of Scrubby Creek in Kingston, from where police dredged it up yesterday, hauling it out with a crane as the stench of decomposing bodies filled the air.

Police load a metal box onto a van after pulling it from a dam in Logan. Picture: AAP Image/Dan PeledSource:AAP

Supt Hutchinson said the accused were allegedly part of a loose social network and the motive for the killings was “probably” drug related.

Police will allege that Mr Breton and Ms Triscaru were bashed and tied up, stuffed in the toolbox and taken alive to the dam in a 1999 Toyota HiLux detectives are still searching for.

The pair were then allegedly shot in the heads and the box was thrown into the dam, with holes drilled in the sides to make it sink, The Courier Mail reports.

A lawyer for two of the accused killers say they are in a “horrified state trying to come to terms with the details of the allegations”.

“Obviously the gravity of the situation is becoming evident and I have grave concerns about their mental state,” defence lawyer Adam Magill said.

Detectives are still looking for two people they want to talk to over the suspected murders of Ms Triscaru and Mr Breton.

However, police have not commented any further on Mr Harrington, or the extent to which he may have helped lead police to yesterday’s grim discovery.

Bodies in a box found in Qld dam3:09

Police fear the bodies of a missing duo are in a metal box found in a dam south of Brisbane.